How to Critically Consider Metabolism Myths – Part 10


We’ve come to the conclusion of our 10-part series on metabolism myths. No longer should your fitness beliefs be shrouded in a cloak of confusion. The fitness world (and especially the internet) is alive and well with claims to help you lose weight, gain muscle and attain that elusive six-pack. Unfortunately, the advice is most often handed out by attention seekers with no real background or credentials in the fitness world.

Your health and fitness goals are far too important to leave in the hands of unqualified individuals who are simply regurgitating information they’ve read elsewhere.

If you’ve missed some of our posts in this series, we’d like to recommend that you swing by and check out our Metabolism Guide, where you can view the full extracts of everything we’ve covered in this series.

Let’s finish up and cover the last myth of metabolism.

Myth #10: It’s important to follow the glycemic index when choosing carbohydrates foods

Three ranges of glycemic indexWhat we’re essentially asking here is, “Is the glycemic index bullshit?”

If you’re not familiar with the glycemic index, it’s a general term that many diets are based on which looks at the effect of carbohydrates on blood sugar.

The index is supposed to assist you in choosing the proper carbohydrate foods. Those with a low GI (glycemic index) rating cause less of an insulin spike since they allegedly create a lesser sugar spike. Remember that insulin is always released in response to carbohydrates to remove sugar from the system.

Carbohydrate foods are given an index “score” from 1 to 100. A carb with a low index is considered desirable. Low GI foods are said to be digested more slowly, thereby causing lesser fluctuations in blood sugar.

The entire glycemic index was originally created to help individuals with diabetes. Since Type I diabetics don’t have a normal insulin response, it’s of great importance to maintain proper blood sugar.

Does GI Help to Lose Weight?

In examining published studies on the glycemic index, there are none that show a significant advantage in separating low and high index carbohydrates.

One major problem with the index is the assumption that insulin response is proportional to glucose response (the conversion of all those carbs to sugar to be used for energy). A Clinical Nutrition study confirms this flawed logic and further concludes that there is not enough data to prove that low GI carbs are in any way superior to high GI carbs1.

Improved blood sugar regulation will occur as a natural result of losing weight on any kind of diet, especially when paired with regular exercise or routine physical activity.

Another problem with the glycemic index is that it assesses index scores based on sugar response alone. This means that healthier foods are often omitted from a diet in favor of those with more sugar. We’re big fans of ice-cream and potato chips, but they’re not ideal foods when trying to achieve your best body or just get healthier. Strangely though, both of these foods have a lower GI rating than baked potatoes with nothing on them.

And this is the allure of diets that promote the glycemic index as a way to lose weight. If you’re considering a GI diet – such as The Zone or Nutrisystem, keep in mind that the glycemic index has little to do with weight loss. People lose weight on these diets due to calorie control – not the effects of low GI carbs.

We’re not knocking those diets – really we’re not! We’re just advising that healthy food choices will add up – and create a healthier “you” – as the years keep moving on.

Before completely dismissing the myth of the glycemic index, it’s worth pointing out that high-glycemic carbs do tend to make people hungrier and more often lead to over-eating. Since carbohydrates on the upper end of the scale are most often of the yummy and sugary variety, this stands to reason. A diet low in carbohydrates can be very effective in assisting with weight control and the majority of low-glycemic foods are healthy choices that can lead to greater satiety. Don’t dismiss carbs altogether though. They have a positive effect on hormones, cellular activity and ultimately your metabolism.

If you’re taking on a new diet that emphasizes carb-control for losing weight, remember that carbohydrates are good for you and allow yourself a variety of carbs. Losing weight and burning fat is a matter of overall calories, not reducing calories and not consuming a particular kind of carbohydrates. That’s just one of many metabolism myths.


  1. http://ajcn.nutrition.org/content/76/1/290S.full 

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